This invention relates to auger boring machines for forming a cased bore underground by boring and pushing casings in a generally horizontal direction from a pit area. In particular, the invention relates to a power and control unit of the boring machine which is efficient to operate and safe for an operator to use.
Earth boring machines are known which are slidably mounted and reciprocated longitudinally along a track in the pit area by means of a hydraulic piston assembly. The forward end of the boring machine has an auger which is rotated within the casings with the forward end of the auger having a cutting head for boring a hole in the earth. The cutting head bores the hole and the auger carries the dirt outward for ejection into the pit area. The hydraulic piston assembly forces the pipe casing through the bore as it is formed. Successive pipe casings are added to the string of pipe casings as the bore progresses. The generally horizontal direction of the string of pipe casings is normally controlled by an articulated steering head section located in front of a forward pipe casing. A power and control unit of the boring machine provides energy for the torque required to rotate the auger and the forces required for the hydraulic pistons to push the boring machine along the track. The power and control unit also provides the operator with a means to modulate or control the amount of energy supplied for rotating and pushing as well as for articulating the steering head.
Typical earth boring machines are disclosed in U.S. Pat. Nos. 3,767,836; 3,851,176; 3,939,926; 4,013,134; and 5,099,927. The boring machines of these references illustrate the basic components of typical boring machines common in the art. The machines are located in a pit area and each are operated by an operator from an exterior to the boring machine itself.
Support equipment located at the top edge of a pit area provides electrical and hydraulic power to support the boring machine within the pit area. The support equipment commonly includes electrical monitoring equipment for tracking the path of the string of pipe casings. Sensors associated with the forward end of the string of pipe casings generate tracking information which can be monitored and plotted for tracking the path of the string of pipe casings. Commonly used sensors include angular rate sensors, rate gyros and accelerometers with integrating circuits, water level gages and distance measuring devices. Some applications of these devices are discussed in U.S. Pat. No. 5,099,927.
Standard boring machines of the present time are built with a diesel or gas engine power unit driving a gear type transmissions connected to a gearbox or speed reducer. The engine produces a torque that drives the transmission that multiplies the torque output to be many times the engine torque. The transmission drives a speed reducer that multiplies the torque again by as much as 100 times. The boring machines vary in size from very small to very large. Some machines provide more than 100,000 foot-pounds of torque to an auger. A fundamental problem with diesel or gas engines is that the exhaust fumes fill the pit area and the air quality must be monitored. It is not uncommon for the workers in the pit area to be required to leave the pit area until the air quality has become safe.
When boring machines are drilling a horizontal bore, the earthen material being encountered at any given time is unknown. To unexpectedly bore into an impenetrable object of earthen material, there can be a violent and dangerous transfer of torque to the boring machine. Boring machine have been known to turn over in the pit area causing damage to the equipment and personal injury to the operator and others. For example, the reaction is similar to a common drill when boring through a wood object and hitting a piece of metal causing the drill's power unit to twist violently out of control in the operator's hand. A typical 36 inch diameter horizontal earth boring machine is manufactured as Model No. 36-600 by American Augers of Underground Technology, Inc. of Wooster, Ohio.
A platform is located on the side of the earth boring machines for the operator to use in accessing the controls that operate the boring machine. The platform is located either on the left side, the right side or on the rear of the boring machine. The operator leans over one side of the boring machine to access the controls, including the gear shift of the transmission. Any sudden movement of the machine can cause the operator to fall into the boring machine and make contact with moving and hot parts of the machine. This does occur frequently with operators which are not experienced.
A push bar is positioned between the two tracks of the standard boring machine to provide a surface for the hydraulic piston assembly to push against when advancing the pipe casings into the bored hole. When the piston assembly is energized the machine moves along the tracks for the length of the piston shaft extension. The push bar is then disengaged from the tracks and relocated to the next position along the tracks. This is repeated until a full section of pipe casing has been pushed into the bore. The nominal length of a pipe casing is 20 feet. The auger is then uncoupled from a drive line and the push bar is unlocked from the tracks. A hydraulic winch is provided at the rear of the boring machine having a cable to be hooked to the rear of the boring machine and activated to return the boring machine to its original starting position along the tracks. Another one of the dangers in operating the standard boring machine is associated with the cable of the winch becoming suddenly disconnected and whipping through the air in the pit area.
Machines that are operated from a rear platform usually have a manual foot-operated pedal for unlocking and relocating the push bar from the tracks. This arrangement further subjects the operator to dangers associated with being off-balance while operating the foot-operated petal. The push bar is located under this rear platform and has been a source of severe injury for the operators's feet.
After moving the boring machine to its starting position another section of pipe casing and another auger section is added to the pipe string and auger in the pit area. The push bar is also relocated to its initial position for the hydraulic piston assembly to again push against. The sequence described above is repeated until the full predetermined length of the bore has been cased with pipe casings and the forward pipe casing and the steering head section have been recovered.
Accordingly, an object of the present invention is to provide a power and control unit which may be personally operated in an earth boring machine pit area in a safe and reliable manner.
Another object of the present invention is to provide an earth boring power and control unit which reduces the possibility of a boring machine turning over in a pit area causing injury of death to an operator and others working in the pit area. Excessive torque capabilities that cause boring machines to turn over are reduced by replacing the commonly used diesel engine and placing the operator in a safe position protected by a structural protecting frame or cab.
Another object of the present invention is to provide a power and control unit which reduces the dangers associated with a hydraulic winch and cable used in the pit area for moving components in the pit area relative to each other prior to installing another pipe casing. This object is to further provide smooth safe hydraulic travel of the power unit on the track system in the pit area.
Yet another object of the present invention is to eliminate the danger associated with moving the push bar along the track system for adjusting the location of the push bar to allow pushing of the string of pipe casings to continue.
A further object is to eliminate exhaust fumes and noise levels in a pit area associated with the operation of diesel engines. A quiet power source capable of maintaining the proper environmental conditions is a part of this object.